The present invention relates in general to phase converters in electrical systems for transmission of electrical energy.
A phase converter was first disclosed in U.S. Pat. No. US427,978 of Dolivo-Dobrowolsky, which deals with a method of obtaining a three-phase electric signal in an electrical system.
Many frequency-based methods for conversion of a single-phase electric signal into a three-phase electric signal via a permanent current with the use of converters are known. All of them however involve significant electrical power losses.
It is known to convert electrical signals by converters for their transmission through one wire or several wires, which are disclosed for example in Single-wire electrical energy transmission by Nikola Tesla (U.S. Pat. No. 1,119,736); The Goubau line, A single-wire transmission line at microwave frequencies. (Geog Goubau, “Surface waves and their Application to Transmission Lines,” Journal of Applied Physics 21 (1950); AFEP experiment based on the Russian patent application by S. and K. Avramenko (PCT/GB93100960). In these converters, the phases of the signals do not actually change, but their frequency increases or their shape changes from AC to DC.
These methods which use known converters have substantial disadvantages in that they are expensive to build and install, the parameters of resulting signals depend on changes of a load, and the systems which use these methods are not reversible.
U.S. Pat. Nos. 9,608,441 and 9,246,405 disclose methods for conversion of one-phase or three-phase signals to provide a single-line systems. In these methods phases of input signals are made identical by means of phase shifters, and then there are added to each other. A disadvantage of these methods is dependence of phases of shifts from resistances of loads. The values of these resistances can vary in the process of use of the systems.